1
As soon as spring brings a new growth of bushes and berries, bears start feeding. They eat and eat. All through the spring and summer their feeding goes on. The bears build themselves up. They store food and fats that they will need in the fall when they start their long sleep.
As days grow shorter, and the temperature begins to fall, bears hunt for a sleeping place. It may be a shallow cave, or a deep crack between rocks. Some bears end up sleeping in hollow logs. Logs seem to be bears’ favourite places. Bears seem to choose small spaces. They can keep warmer in a cave that’s just large enough to hold them than in a larger cave. They often line their sleeping place with leaves and dried grass.
All through their winter naps, bears will not eat. Often they will sleep for 7 months, moving only now and then.
2
Many lands that had once been swamps were drained or filled in. There are different reasons why people drained swamplands. Some were drained to fight diseases caused by insects that lived in them. Because swamps were considered unpleasant places in which to live and harmful to health, many people thought that unless they were drained the land was worthless.
Other swamps were drained to make new land. As the population grew and more land was needed, people drained swamps or filled them to make room for more farms and factories, more roads and airports.
Few people thought that it might be harmful to get rid of swamps. As swamps disappeared, other things happened. There were both more floods and more droughts than before. There were also more fires, for swamps had acted as firebreaks. Hunters noticed that there was less wild game. Wild life that once lived in the swamps was dying out, because it had no place to live.
3
Until fairly recently, it was a mystery how certain large bees, bumblebees in particular, were able to fly. To scientists who study the physical laws of flight a bee’s body seemed too heavy and its wings too small for it to become airborne and remain so. Bees “can’t” fly… but do. The mystery became so intriguing that a few scientists decided to study it.
Most insects fly by using muscles that flap their wings with great speed. For example, the locust beats its wings at a rate of about 20 times per second to fly. Other flying insects have to beat their wings even faster – some as rapidly as 100 times per second. But bees must work extra hard to become airborne. Honeybees, for instance, must beat their wings about 200 times a second to fly. Yet larger bees – like bumblebees – whose bodies are heavier, wider, and longer – have to do even better.
4
The mystery of why trees don’t stop growing is still unsolved. Human beings usually stop growing sometime during their teens. Many animals reach full growth within a year. Others are fully grown in just a few years. Birds and insects also stop growing at a certain age. But trees keep growing as long as they live.
Trees live, grow, and reproduce themselves by an amazing process. The thousands of leaves put forth by the tree breathe for it and manufacture its food. Its root system gathers minerals and vast quantities of water. To carry this water to the leaves, the tree is equipped with an intricate circulation system that extends upward from the millions of root hairs through the trunk and branches. The trunk holds the leaves up to the sunlight, sends them water from the roots, and gets food back from them. Then seed sare born in flowers or cones.
5
No single person or culture invented the alphabet – it has evolved over centuries. In order to understand modern alphabets, we must take a trip back through time. Archeologists have discovered cave paintings thousands of years old that document the first forms of alphabets. In fact, some of the oldest alphabetic symbols have been found in the Middle East more than 5,000 years ago.
One of the earliest forms of the alphabet was hieroglyphics. Hieroglyphics were single symbols that stood for entire words. Thousands of characters and symbols were used to represent the words, needs, and lives of early civilizations.
Memorizing of thousands of unique hieroglyphic symbols was a difficult task, so only the most highly educated priests and scholars were experts.
The Latin alphabet, also called the “Roman alphabet”, is the most widely used alphabetic writing system in the world today. This is the system on which the English alphabet is based.
6
Burney Crouss went to school to study the sounds of nature. For 20 years he has recorded the sounds animals make. He has recordings of animal sounds from all over the world.
Burney has made a record of animal songs. It all began when he took some of the sounds and put them together. Last year, he put together a song he called «Jungle Shoes.» It turned out great.
Burney makes the music by taking part of his animal noises and saving them on a computer. He makes each sound play when a key is pressed. Then he asks other musicians to play the keys into songs. Burney believes in working to save nature. He thinks that more people need to take care of our world. The sounds of nature are quickly disappearing.
When he recorded whales in Alaska, he could hear the sound of oil well drilling from fifteen to twenty miles away. It was very loud. He says his goal is to save nature sounds so his children will be able to hear them.
7
Half the human beings who have ever died, perhaps as many as 45 billion people, have been killed by female mosquitoes. Mosquitoes carry more than a hundred potentially fatal diseases including malaria, yellow fever and elephantiasis. Even today, they kill one person every twelve seconds. Amazingly, nobody had any idea that mosquitoes were dangerous until the end of the nineteenth century. In 1877, the British doctor Sir Patrick Manson proved that yellow fever was caused by mosquito bites.
Seventeen years later it occurred to him that malaria might also be caused by mosquitoes. He encouraged his pupil Ronald Ross to test the hypothesis. Ross was the first person to show how female mosquitoes transmit the parasite. Manson went one better. To show that the theory worked for humans, he infected his own son – using mosquitoes carried in the diplomatic bag from Rome.
8
Some paintings found in different caves around the world are recognized as the work of Stone Age artists. But what was the purpose of the paintings? Why were they hidden in a dark room where there is no evidence that cave people lived?
No one really knows, but there is one theory that makes great sense. It is called the theory of Sympathetic Magic. According to this, the cave people believed that if they could make a likeness of an animal, they could put a spell over it. This spell would give the tribe power over the live animal.
Stone Age existence depended on killing animals — for food, clothing, and even weapons and tools. The animals were large and fierce; the cave people had only the most simple weapons. Hunters had to be brave and fearless. They needed more than a spear or club; they needed all the magic they could get. The magic could help the hunters catch the animals.
9
Mountain gorillas live in the dense forests of Central Africa and are one of man's closest relations in the animal kingdom. They live in family groups and spend the day eating plants. Every evening each gorilla builds a nest to sleep in.
Mountain gorillas are black, and have evolved very thick fur so that they can withstand the cold mountain air. An adult male is called a silver back because of the silver-grey fur that grows on its back when it reaches maturity. A silverback is about the same height as an average man but heavier. Females are much smaller.
The destruction of their natural habitat is a serious threat to gorillas. Illegal hunting and trading are also a problem. Tourism helps to finance the ongoing efforts to save this endangered species. A few companies organise gorilla safaris so that people can see these amazing creatures at first hand. Some of the money from these tours goes to wild life organisations to protect the gorillas.
10
Half the human beings who have ever died, perhaps as many as 45 billion people, have been killed by female mosquitoes. Mosquitoes carry more than a hundred potentially fatal diseases including malaria, yellow fever and elephantiasis. Even today, they kill one person every twelve seconds. Amazingly, nobody had any idea that mosquitoes were dangerous until the end of the nineteenth century. In 1877, the British doctor Sir Patrick Manson proved that yellow fever was caused by mosquito bites.
Seventeen years later it occurred to him that malaria might also be caused by mosquitoes. He encouraged his pupil Ronald Ross to test the hypothesis. Ross was the first person to show how female mosquitoes transmit the parasite. Manson went one better. To show that the theory worked for humans, he infected his own son – using mosquitoes carried in the diplomatic bag from Rome.
